The present invention relates to X-ray counting circuit technology for an energy dispersive X-ray analyzer.
In an X-ray counting section of an energy dispersive X-ray analyzer, a counting efficiency representing a ratio of incoming X-rays to X-rays actually counted, and an energy resolution for the acquired energy spectrum are mutually conflicting elements. There are differences in absolute values due to performance of respective devices, but there is a relationship such that if the energy resolution is made good the counting efficiency becomes poor, while if the counting efficiency is made good the energy resolution becomes poor. The reasons for this are as described in the following. In order to obtain a satisfactory resolution, more information is required. What this means in actual fact is that the processing time per X-ray input is required to be longer. In the event that the next X-ray is input within the processing time, the information of the X-ray input before is disrupted by the X-ray information input later, which means that those two signals become discarded. Since X-ray input is a random phenomenon, making the processing time longer in order to improve resolution will increase the probability of subsequent X-rays being injected during processing causing discard of data, and counting efficiency will become worse. As a result, a processing time having a suitable balance between energy resolution and counting efficiency is selected depending on the use.
In a conventional energy dispersive X-ray analyzer, this processing time, namely a balance between energy resolution and counting efficiency, is generally the same across detectable energy regions.
Accordingly, in actual application, there are many instances where the same energy resolution is not required for all regions. In these type of cases, unnecessary signals that conventionally require a long processing time, such as those for energy regions that are not of interest for application or energy regions that have no application problems for the reason of being separated from the energy of characteristic X-rays, also contribute to worsening of the counting efficiency, and there is a problem that an unnecessarily long time is expended on measurement. With the present invention, attention is paid to this point, and the purpose is to provide an energy dispersive X-ray analyzer that can perform efficient measurement, by optimizing signal processing time of an X-ray counting section.
In order to achieve the above stated purpose, an energy dispersive X-ray analyzer of the present invention is provided with an energy dispersive X-ray detector for detecting X-rays and outputting a signal containing energy information of detected X-rays, an X-ray counting section for analyzing the signal from the energy dispersive X-ray detector and generating a frequency distribution for each energy, namely an energy spectrum, and a data control section for performing data processing, and user interface etc. The X-ray counting section of the energy dispersive X-ray analyzer has signal processing methods with different processing times per X-ray input, and a function for selecting which method to make use of using input X-ray energy.